The standard vehicle restraint system has a lap belt portion and a shoulder belt portion. It is considered advantageous to have the shoulder belt section rather loose to allow the vehicle occupant freedom of movement of his upper torso. It is not considered advantageous to allow freedom of movement to the lower torso, and the lap belt on conventional vehicle restraint systems is adapted to hold the lower torso tightly in the vehicle seat.
Many systems include two retractors, one for the lap belt and the other for the shoulder belt. The belts are generally attached to a connector plate which can be buckled into a floor buckle. But, retractors are somewhat expensive, and systems utilizing only a single retractor are advantageous. In such systems, one end of the webbing is attached to the retractor, and the other end is secured to an anchor on the vehicle. A connector which is free to move along the webbing is buckled into a floor mounted buckle, and the webbing is positioned across the lap and shoulder of the vehicle occupant.
One problem with such a system is that the length of the lap belt portion and the shoulder belt portion is not fixed, and the webbing can slip through the connector. As discussed above, it is especially important that the lap belt portion be tight, and slipping of the webbing through the connector after buckling may permit the occupant to move his lower torso and loosen the lap belt portion.
It has been suggested to have a one-way fitting for the webbing that allows passage of the belt in a direction that tightens the lap belt portion and feeds the webbing into the shoulder harness section. See, for example, Sharp, U.S. Pat. No. 3,258,293 (1966). Although the one-way fitting prevents slippage of the webbing which would loosen the lap belt portion, the system itself does not prevent buckling with a loose lap belt. The occupant must pull on the buckle from the shoulder harness portion to tighten the lap belt portion. Although many users will follow these instructions, one who does not is subject to increased risk in the event of a crash.
It has been recognized that it is possible to use a retractor to tighten a portion of the loop or webbing. See, for example, Carter, U.S. Pat. No. 3,606,455 (1971). When the shoulder harness section is attached to the retractor, which, as discussed above, is advantageous from a safety point of view, different criteria than those recognized in Carter must be satisfied. Normal retractors are powerful enough only to wind loose webbing. The springs do not have enough force to pull the webbing through a frictioned connector. Therefore, it is an object of the present invention to provide a continuous loop restraint system for use in vehicles which will maintain the lap belt portion of the webbing in a tight condition. A further object of the present invention is to have a tight lap belt portion with the retractor attached to the shoulder harness portion in the upper part of the vehicle.
Although one-way connectors for restraint systems have been proposed, the prior art connectors either allowed some slipping between the various webbing portions, or they presented difficulties in adjusting the length of the various webbing sections. It is also important that the one-way feature in the connector be releasable so that the length of the lap belt portion can be adjusted. Therefore, it is another object of the present invention to provide for such adjustments in a manner that will not lead to slipping of the webbing in a wrong direction through the one-way connector when the connector is buckled but will permit movement in that direction prior to buckling to permit adjustments in the webbing lengths.
Another object of the present invention is to provide means whereby the lap belt is tightened automatically without even minimal effort required by the user. Still a further object of the present invention is to allow the above-stated objects to be met while permitting some freedom of movement of the upper torso to allow the vehicle occupant to move around slightly and to lean forward or to the side so that he can reach objects within the vehicle. It is a further object of the present invention to provide for automatic tightening of the lap belt portion while eliminating excess pull from the retractor on the shoulder harness.
These and other objects will become evident from the description of the invention.